1. Field of Invention
The disclosure herein relates to nozzles for use with earth boring bits. More specifically, the present disclosure concerns nozzles configured with a notch to create a spray pattern for cleaning earth boring bits.
2. Description of Prior Art
Drilling systems having earth boring drill bits are typically used in the oil and gas industry for creating wells drilled into hydrocarbon bearing substrata. Drilling systems typically comprise a drilling rig (not shown) used in conjunction with a rotating drill string wherein the drill bit is disposed on the terminal end of the drill string and used for boring through the subterranean formation. Drill bits typically are chosen from one of two types, either drag bits or roller cone bits. Drag bits typically have no moving parts on the base and shear the formation by the cutting elements on its surface. These cutting elements may comprise an outer surface of polycrystalline diamond compact (PDC) bits and some have diamond impregnated bits on their surface. Roller cone bits or rotary cone bits typically have one or more conic roller cones with cutting teeth on the outer surface of the cone. Rotating the bit body with the cutting elements on the outer surface of the roller cone body crushes the rock and the cuttings may be washed away with drilling fluid.
Drilling fluid may be introduced into the cutting process by a nozzle disposed on the cutting phase of either a drag bit or a rolling cone bit. These spray patterns typically are conically shaped and directed against the cutting elements. The high pressure of the spray impinging on the cutting elements cleans the surface of the cutting element by removing debris which enhances drilling. The high pressure fluid also captures detrius and other bits of downhole debris carries it up through the bore hole as it flows to the surface. One problem with the conical spray pattern is it impinges on other components within the particular drilling bit, which due to the erosive nature of the fluid, i.e. can prematurely wear away other portions of the drilling bit.
In the case of the PDC bits, cutting is performed by shearing away the subterranean formation thereby producing shavings that are larger than those of a conventional diamond bit. Accordingly, typically nozzle tips for the drilling mud are disposed proximate to the formation surface than wherein the fluid flow of the drilling fluid not only serves to transport the cuttings away from the cutting surface but also helps erode pieces of the rock and structure beneath the drill bit. Thus, efficiently removing the cuttings serves to prevent recutting of rock fragments thereby reducing the stress on the drill bit. The number of nozzles on each of these different types of bits depends on the bit size and the arrangement of the cutting elements on the face of the individual drill bit. Accordingly, the total flow area of the nozzles is determined by first evaluating the requirements of hydraulics for the particular drilling situation. Thus, the nozzle flow area depends on these hydraulic requirements, should the nozzle cross sectional area be of a sufficiently small value, the chances of plugging in the nozzle are increased. Moreover, the life of a drill bit having a PDC cutter face is typically extended when it is adequately lubricated and cooled during the drilling process by the drilling fluid. In contrast, having inadequate fluid flow to the face of a PDC cutter allows formation cuttings to collect on the faces of the cutting elements. This collection of cuttings isolates the cutting elements from the drilling fluid. This also reduces the rate of penetration of the drilling bit and if the debris collection is sufficiently high the cutting elements may overheat which increases the wear rate.